A 28-year-old woman with newly diagnosed sputum-positive pulmonary TB is started on standard anti-TB therapy (HRZE for 2 months, then HR for 4 months). She is 8 weeks into treatment and reports new-onset jaundice, dark urine, and right upper quadrant pain. Liver function tests show: ALT 320 U/L, AST 280 U/L, ALP 180 U/L, total bilirubin 4.2 mg/dL. What is the most appropriate next step in management?